Well the subject says it all :'( :'( :'(
Do you know where you installed mx-bikes?
Right-click the icon for MXB and click properties. Click on "Open Target Location", that's the MXB folder. Right-click and click "New/Folder" and name it bikes. Do it again for tracks. Now you have destination folders for all of the user created content! P.S. Make sure you don't have the problem of "Folder-in-folder". Example: Tracks/Gravel Pit/Gravel Pit/. It should just be...Example: Tracks/Gravel Pit/